Fully relativistic calculation of nuclear magnetic shieldings and indirect nuclear spin -spin couplings in group-15 and -16 hydrides

S. S. GOMEZ; R. H. ROMERO; G. A. AUCAR

JOURNAL OF CHEMICAL PHYSICS

Año: 2002 vol. 117 p. 7942 - 7946

0021-9606

Fully relativistic calculations of the isotropic and anisotropic parts of both indirect nuclear spin spin couplings 1J(X-H) and 2J(H-H) and nuclear magnetic shieldings s(X) and s(H) for the group-15 and -16 hydrides are presented. Relativistic calculations were performed with Dirac Fock wave functions and the random phase approximation method. Results are compared to its nonrelativistic counterpart. Paramagnetic and diamagnetic contributions to the nuclear magnetic shielding constants are also reported. We found very large relativistic corrections to both properties in the sixth-row hydrides (BiH3 and PoH2). Our calculations of the relativistic corrections to the isotropic part of s at the heavy nucleus X show that it is roughly proportional to Z3.2 in both series of molecules. Paramagnetic term sp is more sensitive to the effects of relativity than the diamagnetic one sd, even though both have a behavior proportional to third power of the nuclear charge Z.